Aims and background: Non-melanocytic skin cancers are the most common cancers in white populations. Studies on populations of Anglo-Saxon and Mediterranean origins highlighted different patterns of risk of basal-cell carcinoma and squamous-cell carcinoma in relation to sunlight exposure, skin characteristics and phenotype susceptibility. In Sion, and in Switzerland as a whole, the high incidence suggests the possible presence of additional risk factors or of a different pattern of exposure to solar radiation as well as different composition of pigmentary traits and skin sensitivity to sun.
Methods and study design: We conducted a case-control study of 146 cases (73% of eligible cases) and 144 controls (81% of eligible subjects) to further evaluate the relationship between nonmelanocytic skin cancer and risk factors in the Sion population. Interviews were conducted by trained interviewers with a standardized questionnaire.
Results: Pigmentary characteristics such as blonde and red hair as well as tendency to sunburn without tanning and number of sunburns showed a statistically significant and independent risk increase in basal-cell carcinoma. Sun exposure during recreational activities (outdoor sports) showed a risk increase in basal-cell carcinoma with borderline statistical significance. Analysis of squamous-cell carcinoma risk was limited by the small number of cases, but it was positively associated with lifetime exposure to sun during outdoor work and with skin characteristics.
Conclusions: Results confirmed previous suggestions of a different mechanism leading to malignant transformation of target cells from the basal and squamous epidermal layers, mediated by different phenotypes, and conditioning the ability to develop an effectively protective tan.